How to model Yin Yang sphere?
Thanks to Jachym Michal and Duarte Farrajota Ramos, I made it!

You can download Blend File for free from
https://gum.co/yin_yang_sphere_blend
The procedure is as follows:

Add UV Sphere (Radius = 1m)
Add Plane (Size = sqrt(2), RotationX = 90)
Select Plane -&gt; Convert to -&gt; Curve from Mesh/Text
Edit Plane -&gt; Extrude vertex to make square with diagonal line (Turn on Vertex Snap mode)
Finish editing Plane
Select Plane then UV Sphere
Go into Edit mode -&gt; Knife Project (Cut through = ON)


Step 1-3

Step 4-5

Step 6-7

Assigned materials (white, black and transparent)

NOTE: If you look closely at the reference video, the inner surface of the sphere is slightly raised.

My model doesn't have that part, so if you set the camera to the angle where you can see the Yin Yang plane, a small circle will be distorted horizontally.

Unfortunately, this seems to be the limit for non-mathematical modeling.